Acoustical construction



J. MAZER April 20, 1937.

ACOUSTICAL CONSTRUCTION Filed Feb. '7, 1936 INVENTOR QLM m ATTORNEYSPatented Apr. 20, 1937 UNITED STATES PATENT OFFICE 6 Claims.

cult to meet, for the normal soft bodies which might be used as spacingelements ordinarily do not have sufficient strength to hold the facing 5sheet from pulling away from the backing element, and where the strengthis obtained this is done with the sacrifice of the necessary softness.Thus if superimposed layers of felt are used there is generally a lackof strength unless the felt is compressed or impregnated to such anextent that the cushioning action is largely destroyed.

I have found that this problem can be solved very efficiently andinexpensively by using a felted material preferably of a homogeneousnature and attaching it in spaced bands to the facing sheet withflattened loops between the bands for attachment to the backing element.It will be found that the felts, even when quite soft, have a surprisingtensile strength and this factor is utilized when the loop arrangementis employed. For this purpose I may use hair felt but I find thatparticularly efficient and inexpensive results can be had with ragfelt-the cheap material made from old rags which is now principallyemployed for roofing, after being impregnated with asphaltic material.

In utilizing the felt, it should be attached to the facing materialalong spaced bands broad enough to give a substantial zone ofattachment. Loops are left between these attachment bands and theseloops should be large enough relative to the spacing between the bandsso that when the loops are flattened as during attachment to the backingelement, the edges of the loops adjacent the backing element willoverlie the flattened portions of the felt contacting (or approximatelycontacting) with the facing sheet. By arranging the loops in this mannerit is evident that the cushioning and spacing effect does not dependupon the stiffness of the felt, for

. this construction will result in substantial rows where the zones ofoverlap occur, such that if pressure is applied this pressure will betaken up with an actual compression of the felt, as 65 well as utilizingits springiness resulting from the fact that it is creased back uponitself. Such overlap may be of relatively small area or the loops may beso large relative to the spacing as to approach the point where therewill be substantially three thicknesses of the felt at all pointsbetween the backing and facing elements when the mass is compressed.Even when the loops are of this size, under normal circumstances therewill be enough spring in the felt so that voids of substantial volumewill be formed to give a soft cushioning relationship.

By the arrangement of loops above described, the spacing between thefacing sheet and the backing element normally will be at least twice andunder some circumstances more than three times the thickness of the feltemployed. As stated above, it is desirable to have the facing sheet heldat least one-quarter inch and preferably more than three-eighths inchfrom the backing element and accordingly I prefer to use a relativelythick felt. However, this invention can be applied to thin felts, andvaluable results can be obtained using this invention even though thespacing between the facing sheet and the backing element is considerablyless than one-quarter inch, the important feature for the purpose ofthis invention being that the felt shall run back and forth to givestrength, and have such thickness and texture that the overlappinglayers will ive a cushioning action even when pressed down so that theyare in contact with each other.

It is, of course, permissible that the loops when first formed byattachment of the felt to the facing sheet should be in the form ofrounded arches, but in such case if the material is rolled up, theseloops will usually be flattened so that When the time comes forattaching the material to the rigid backing element, the loops will haverelatively broad zones for attachment. Usually it will be found mostpractical to apply the adhesive to the rigid backing element and thenpress on the insulating structure.

The best and cheapest material which I have found for use in myinvention is ordinary rag felt laid down rather loosely and formed as anintegral substantially homogeneous sheet. Such I sheet in and of itselfhas sufficient strength for my purpose both when subjected tolongitudinal strain and also as resisting a tendency to separate intolayers and thus cause the facing sheet to leave the backing element.There is no reason why this felt should not be surfaced with materialsuch as paper if desired, nor why two or more layers of the felt shouldnot be attached together, but ordinarily there is no particular benefitin such structure and therefore I may state that my invention involvesthe use of a spacing member consisting essentially of soft,approximately homogeneous, sheeted felt thereby intending to imply thathomogeneous felt is a required condition of the invention, but that theaddition of other material such as paper. or the laminating of two ormore layers of such felt is not precluded.

The facing sheet may be of any desired type of flexible material such asfelt, paper or fabric. However for acoustical work the facing sheet ispreferably quite soft, and I have found that if a substantially flatsheet of material is used such aspaper or felt, there is a tendency forthis to be drawn out of the true plane by the contours of the spacingelement, and also there is a tendency for it to be creased or bent whenthe structure is rolled for shipment. These distortions tend to show upwhen the structure is applied to a wall or ceiling, and in order torender them less obvious I have found it advisable to form the facingsheet with an uneven surface. This may be done by creping, embossing orotherwise shaping the facing sheet itself or I may form the facing sheetof two members, one of which is a flat sheet of such material as felt orpaper and the other is a surfacing sheet which has previously beenembossed, creped or creased in such a way that the distortions resultingfrom handling the structure will not be noticeable. For example, I havefound that particularly attractive appearances can be had by using anembossed sheet of asbestos paper for the coating sheet, or by usingmetal foil for this purpose which has been embossed or preferably bothcreased and embossed as described in my co-pending application, SerialNo. 62,740 filed Feb. 7, 1936. i 1

By having the facing sheet formed of a flat member and an embossedmember, additional softness is given to the facing sheet due to the factthat the two will not be united over their whole area and this softnessgives additional acoustical qualities to my product. It is alsopermissible under the spirit of my invention to perforate the facingsheet which gives added acoustical qualities as is well understood inthe art. In this particular case the perforations have particular value,for some of them lead to the soft felt and others will lead to thechannels'formed by theinside of the loops and thus there will beparticularly emcient absorption of the sound waves.

The backing element preferably is a rigid portion of the buildingconstruction such as a plaster wall, or a wall or ceiling otherwise putup, and in the finished installation this will usually be the onlybacking element employed. However, under some circumstances,particularly if ability to roll up the insulating material for shipmentis not of importance, or if the material is to beemployed for insulationsuch as sound deadening, the spacing member may be attached to anydesired type of sheeted element in advance of installation, and this inturn may later be attached or connected to the wall, ceiling or otherstructural element and thus become a part of the ultimate construction.

My invention is illustrated in the accompanying drawing, in which Fig. 1shows a section through a wall to which a structure embodying myinvention has been applied; Fig. 2 is a perspective view of a portion ofa sheet of composite material forming the structure of my invention, inwhich the loops have been approximately flattened as they would be byrolling, and where the loops are larger relative to the spacing betweenthe attachment bands than is the case in Fig. 1.

In Fig. 1 the numeral l0 indicates a wall of ordinary construction whichmay for example be faced with plaster; (the term wall" is intended toinclude a ceiling). I2 is the facing sheet which is held in spaced andcushioned relation to the wall I0 by the spacing element H which isformed of a felt such as rag felt, and is attached to the facing elementI2 in spaced bands, and is provided with loops that are here shownattached to the wall l0. It will be noted that the edges of the loopscontacting or approximately contacting with the wall i0 overlie theportions of element H which contact or substantially contact with thefacing sheet, so that compression lines or rows are supplied which willresist pressure exerted against the facing sheet. Such pressure willfirst bend the felt somewhat to bring the overlying portions intocontact, and further pressure will compress these overlying portions togive a resilient cushioning action.

In Fig. 2 the facing sheet is shown as made of a flat facing member orliner sheet It to which is attached an embossed or creped covering sheetIII which may be made of ordinary paper or metal or of asbestos paper.In this case it will be noted that while in general the covering sheetIt! will bear against the facing member l6 for attachment, it will alsohave ,raised portions resulting from the embossing, creping or otherfolding or creasing operations which stand away from the facing member.Suchraised portions may serve somewhat to increase the resilience of thesurface and thereby improve the acoustical qualities as well as addingto the appearance of the product. The spacing member 20 of Fig. 2 isattached to the sheet it by bands which are relatively close together,and comparatively large loops are.

formed between these bands which are here shown as more or lessflattened as they would be by rolling for shipment. With thisarrangement the actual compression of the felt would become more of afactor in the cushioning value of the structure but in general itsaction would be similar to that of the structure shown in Fig. 1. a

While my invention is primarily intended for attachment to walls andceilings as a soundabsorbing medium to improve acoustical qualities, italso may be used for other purposes such as for sound deadening or otherinsulating uses.

It is to be understood that the examples shown are intended only by wayof illustration.

What I claim is:

1. A structure adapted for use for acoustical purposes on the walls orceilings of buildings, comprising a facing sheet and a spacing memberattached thereto, such spacing member consisting essentially of softcompressible approximately homogeneous sheeted felt which is attached tothe facing member along spaced bands with loops extending back betweensuch bands adapted for attachment to a backing element said loops beinglarge enough so that under pressure they will form a series of soft,compressible rows of overlapping material to hold the facing sheetspaced from such backing element.

2. A structure as specified in claim 1, in which the loops are largeenough so that when flattened by pressure as during attachment to abacking element, the edges of each loop will overlie two adjacent bandsapproximately contacting the facing member.

3. An insulating structure consisting essentially of a facing sheet anda spacing member 5-formed of a homogeneous sheet of compressible softragfelt attached to the facing sheet alon spaced bands with flattened loopsextending back between such bands whereby such facing sheet may beattached to a rigid surface in 10 spaced relation thereto, said loopsbeing large enough so that when flattened they will form a series ofrows of overlapping material to hold such facing sheet cushionedrelative to such rigid surface by the compressibility of the rag 15felt. 4. A structure for sound deadening or sound absorption consistingessentially of a facing member carrying a covering sheet having portionscontacting with the facing member and 20 portions raised relativethereto, and a spacing member adapted to hold such facing member inspaced and cushioned relation to a wall member, saidspacing memberconsistingessentially of a sheet of soft, compressible felt attached tothe facing member by spaced loops and having intermediate soft, flexibleloops running back for attachment to a wall, whereby the longitudinaltensile strength of the felt will serve to hold the facing sheet fromleaving the wall and the compressibility of the felt will hold thefacing sheet in cushioned relation to the wall. I

5. A structure as specified in claim 4, in which the covering sheet isformed of sheet asbestos.

6. A wall structure having a usual rigid approximately fiat surface, afacing sheet for such wall, and cushioning attachment means for suchfacing sheet consisting essentially of a sheet of soft compressible ragfelt running back and forth between the facing sheet and the flatsurface and attached to the wall and facing sheet along spaced bands theportions of the sheet of felt along the facing sheet being large enoughto overlie portions of such sheet along the wall with approximatelyperpendicular portions con necting the same to form a series ofcompression ribs.

JACOB MAZER.

